Here are some 2x3 eye suggestions that I created that I hope get added! :-)

Bottom 2x3 Eyes, Bottom Pupils

Lower Mid 2x3 Eyes, Top Pupils

Lower Mid 2x3 Eyes, Bottom Pupils

My Skin has the bottom configuration of 2x3 eyes. I'd be very thankful if they got added!

Also I think if you want the first arrangement, since the animations put the pupil in the middle anyways and the entire eye gets replaced, you could just have it show up on your skin how you want it and use the pixel positions of the 2x3 eyes that are implemented currently. I think that should work

Okay, I just checked the positions of all the eye types, and the only position that wouldn't conflict with anything (like the bottom two here conflict withe the enderman style eyes), is to the right of the original 2x3 eyes, right next to them.
Another set should fit there perfectly. Pretty much everywhere else is already taken up by other things.
Unless this area is used for something else that isn't shown in the documentation, this should be a good spot to add the higher 2x3 eyes.

I totally forgot about position conflict! Glad you mentioned this in the thread.